Method and apparatus for selecting and receiving stream in distribution network-based multimedia streaming service

Abstract

A method and an apparatus for selecting and receiving a stream in a distribution network-based multimedia streaming service are disclosed. According to the method, a receiving apparatus receives an index file for a channel from an index server and obtains a time difference between a current time of the receiving apparatus and the start time of the first streaming from the index file. Then, the receiving apparatus selects a fragment including a stream to be received among a plurality of fragments in which multimedia streams are divided and requests the selected fragment.

What is claimed is: 
     
       1. A method for selecting and receiving a stream in a multimedia streaming service, comprising:
 requesting, by a receiving apparatus, information on a streaming session from an index server; 
 receiving, by the receiving apparatus, session information from the index server; 
 calculating, by the receiving apparatus, a time difference based on the session information; and 
 checking, by the receiving apparatus, a status of fragment generation based on the time difference; 
 selecting, by the receiving apparatus, an appropriate fragment based on the status of fragment generation; and 
 requesting, by the receiving apparatus, fragments from the selected appropriate fragment. 
 
     
     
       2. The method of  claim 1 , wherein
 the session information includes a time when an initial multimedia stream to be distributed is created, a date when the initial multimedia stream to be distributed is created, and a Greenwich mean time (GMT), wherein 
 the calculating of a time difference comprises 
 calculating the time difference based on the time, the date and the GMT. 
 
     
     
       3. The method of  claim 2 , wherein
 the calculating of a time difference comprises 
 calculating the time difference by comparing the time when the multimedia stream to be distributed is created with a current time of the receiving apparatus based on the date and the GMT. 
 
     
     
       4. The method of  claim 2 , wherein
 the session information further includes data related to a keyframe interval, wherein 
 the checking of a status of fragment generation comprises 
 knowing a period for generating a fragment based on the data; and 
 determining a latest fragment based on the time difference and the period for generating a fragment. 
 
     
     
       5. The method of  claim 4 , wherein
 the data related to a keyframe interval is a keyFrame-interval-inSec that indicates a keyframe interval in second and a value of the KeyFrame-interval-inSec is n, wherein 
 the knowing of a period for generating a fragment comprises 
 knowing the period for generating a fragment in which a fragment is created in every n seconds based on the keyFrame-interval-inSec. 
 
     
     
       6. The method of  claim 4 , wherein
 the data related to a keyframe interval is a framerate and a keyFrame-interval-inFrame that indicates a keyframe interval in frame, wherein 
 the knowing of a period for generating a fragment comprises 
 obtaining the period for generating a fragment by dividing the keyFrame-interval-inFrame by the framerate. 
 
     
     
       7. The method of  claim 4 , wherein
 the session information further includes a bit rate of a multimedia stream, wherein 
 the selecting of an appropriate fragment comprises 
 selecting an appropriate fragment in consideration of a size of a fragment, the period for generating a fragment and the bit rate of a multimedia stream. 
 
     
     
       8. The method of  claim 7 , wherein
 the session information further includes an encoding type, wherein 
 the selecting of an appropriate fragment further comprises 
 deducing the size of a fragment by referring the period for generating a fragment and the bit rate of a multimedia stream according to the encoding type. 
 
     
     
       9. The method of  claim 8 , wherein
 the selecting of an appropriate fragment comprises 
 deducing an expected delivery time of a fragment based on the size of a fragment and its available downlink bandwidth; and 
 selectin an appropriate fragment based on the expected delivery time of a fragment. 
 
     
     
       10. The method of  claim 9 , wherein
 the selecting of an appropriate fragment based on the expected delivery time of a fragment comprises 
 selecting an appropriate fragment according to the expected delivery time of a fragment so that a next fragment is received before playing of a previous fragment is completed. 
 
     
     
       11. The method of  claim 10 , wherein
 the selecting an appropriate fragment according to the expected delivery time of a fragment selects an appropriate fragment in further consideration of a fragment processing time in addition to the expected delivery time of a fragment. 
 
     
     
       12. The method of  claim 1 , wherein
 the session information further includes a bit rate of a multimedia stream, wherein 
 the selecting of an appropriate fragment comprises 
 selecting a latest fragment based on the status of fragment generation, and 
 the requesting of fragments comprises 
 comparing its available downlink bandwidth and the bit rate of multimedia stream; and 
 requesting the latest fragment if the available downlink bandwidth is greater than the bit rate of multimedia stream. 
 
     
     
       13. The method of  claim 2 , wherein
 the session information further includes data related to a keyframe interval, a bit rate of a multimedia stream, and an encoding type, wherein 
 the data includes a keyFrame-interval-inSec that indicates a keyframe interval in second or the data includes a framerate and a keyFrame-interval-inFrame that indicates a keyframe interval in frame, and 
 the encoding type includes constant bit rate (CBR) or variable bit rate (VBR). 
 
     
     
       14. An apparatus for receiving a stream in a multimedia streaming service, comprising:
 a network interface device configured to communicate with other devices through a network; and 
 a processor connected with the network interface device and configured to select a stream to be received, wherein 
 the processor is configured to:
 request information on a streaming session from an index server; 
 receive session information from the index server; 
 calculate a time difference based on the session information; 
 check a status of fragment generation based on the time difference; 
 select an appropriate fragment based on the status of fragment generation; and 
 
 request fragments from the selected appropriate fragment. 
 
     
     
       15. The apparatus of  claim 14 , wherein
 the session information includes a time when an initial multimedia stream to be distributed is created, a date when the initial multimedia stream to be distributed is created, a Greenwich mean time (GMT), data related to a keyframe interval, a bit rate of a multimedia stream, and an encoding type, wherein 
 the data includes a keyFrame-interval-inSec that indicates a keyframe interval in second or the data includes a framerate and a keyFrame-interval-inFrame that indicates a keyframe interval in frame, and 
 the encoding type includes constant bit rate (CBR) or variable bit rate (VBR). 
 
     
     
       16. The apparatus of  claim 15 , wherein
 the processor is configured to 
 calculate the time difference by comparing the time when the multimedia stream to be distributed is created with a current time of the receiving apparatus based on the date and the GMT, 
 know a period for generating a fragment based on the data; and 
 determine a latest fragment based on the time difference and the period for generating a fragment. 
 
     
     
       17. The apparatus of  claim 16 , wherein
 when the data related to a keyframe interval is a keyFrame-interval-inSec that indicates a keyframe interval in second and a value of the KeyFrame-interval-inSec is n, 
 the processor is configured to know the period for generating a fragment in which a fragment is created in every n seconds based on the keyFrame-interval-inSec; or 
 when the data related to a keyframe interval is a framerate and a keyFrame-interval-inFrame that indicates a keyframe interval in frame, 
 the processor is configured to obtain the period for generating a fragment by dividing the keyFrame-interval-inFrame by the framerate. 
 
     
     
       18. The apparatus of  claim 16 , wherein
 the processor is configured to 
 select an appropriate fragment in consideration of a size of a fragment, the period for generating a fragment and the bit rate of a multimedia stream. 
 
     
     
       19. The apparatus of  claim 18 , wherein
 the processor is configured to
 deduce an expected delivery time of a fragment based on the size of a fragment and its available downlink bandwidth; and 
 
 select an appropriate fragment according to the expected delivery time of a fragment and a fragment processing time so that a next fragment is received before playing of a previous fragment is completed. 
 
     
     
       20. The apparatus of  claim 15 , wherein
 the processor is configured to 
 select a latest fragment based on the status of fragment generation, 
 compare its available downlink bandwidth and the bit rate of multimedia stream; and 
 request the latest fragment if the available downlink bandwidth is greater than the bit rate of multimedia stream.